Chemical element · Atomic number 44
Ruthenium
Ruthenium in the periodic table: atomic number 44, electron configuration, atomic mass, physical data, oxidation states, media credit and visible sources.
Transition metal
solid
101.1 u
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Atomic classification
Shell occupancy
Ruthenium in the Bohr shell model
This shows the electron distribution of the neutral atom in a simplified shell model.
- K · n=1
- 2 electrons
- L · n=2
- 8 electrons
- M · n=3
- 18 electrons
- N · n=4
- 15 electrons
- O · n=5
- 1 electron
- Electron configuration
- [Kr]5s1 4d7
- Electrons per shell
- 2 · 8 · 18 · 15 · 1
- Group
- 8
- Period
- 5
- Block
- D
- Element category
- Transition metal
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Physical and chemical properties
- Atomic mass
- 101.1 u
- Standard state
- solid
- Density
- 12.1 g/cm³
- Melting point
- 2,607 K
- Boiling point
- 4,423 K
- Electronegativity
- 2.2 (Pauling)
- First ionisation energy
- 7.361 eV
- Oxidation states
- +3
- Discovery
- 1827
Safety and periodic classification
Safety
Safe handling cannot be inferred from Ruthenium's position in the periodic table alone. Laboratory, classroom and disposal decisions must follow the documentation for the exact material and its safety data sheet.
Position and comparison
Ruthenium is in period 5, group 8 and the D block. Its direct neighbours by atomic number are Technetium and Rhodium. The recorded Pauling electronegativity is 2.2. Periodic trends are compared only through the separately sourced neighbouring values.
Sources and scope
PubChem attributes element data to sources including IUPAC, NIST and IAEA. Quanta stores the referenced snapshot locally and leaves unknown values unavailable.